Re: [ATM] Open Question Concerning Pitch Laps

[Guy Brandenburg <gfbrandenburg@yahoo.com>]

I tend to scratch at the surface of the lap with a the
point of single-edge razor blade, in two orthogonal
directions. It helps some; follow that by a hot press
with mesh.
If these steps don't help, then it's time to chip off
all of the old pitch and melt it down and pour a new
one. It doesn't really take all that long, and it's
better than doing the same old thing with the same old
ineffective lap. It can work marvels, in fact.
Guy
--- Jim Burrows <burrjaw@earthlink.net> wrote:

> At 2005-02-28 16:20 -0500, Bryan Stiles wrote:
> 
> >I tried all the suggestions
> >kindly provided but to no avail...I went back to
> fine grinding. In a
> >nutshell the question is why does my lap quit
> responding?
> 
> Yeah, I agree with the others:  DON'T go back to
> fine grinding!  Anyway, 
> pitch laps tend to lose effectiveness.  I think it's
> due to getting a crust 
> of glass shavings which prevents the polishing
> compound from doing its 
> thing.  Quite a while ago, I wrote a program that
> evaluated lap 
> effectiveness - how much the surface changed vs.
> polishing spell time 
> (looking back in the notes, 16 nm/min once dropped
> to 11 nm/min ).  This 
> was mainly to find how long the next spell should
> be.  The number decreased 
> steadily.  The solution is, as Ken Lowther suggests,
> to brush the lap.  I 
> think, but I'm not sure, an ordinary cleaning brush
> will work, a wire brush 
> being overkill.
> 
>          -- Jim Burrows
>          -- mailto://burrjaw@earthlink.net
>          -- http://home.earthlink.net/~burrjaw
>          -- Seattle N47.4723 W122.3662 (WGS84) 
> 
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> 


=====
Guy  Brandenburg
Washington, DC
My home page:
http://home.earthlink.net/~gfbranden/GFB_Home_Page.html
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